Has there been a recent change to any of the swapping mechanisms? I noticed on my aptosid laptop at home this weekend that despite less than 1/3 of the ~ 3 GiB RAM being used, a lot of data (several hundred MiB, at least) was being moved to the swap partition, for no reason I could discern.

Similarly, on my work desktop after the latest DU, there is tremendous swapping going on.

Hmm. I note that /proc/sys/vm/swappiness, at least on my desktop, is back to 60, whereas I had set it to a much lower number before.

I think that the setting had persisted through several DUs, including kernel updates, but has now reverted to its previous default of 60. I'm going to change it back to 10 (or even 5); if it solves this swappiness problem, I'll post back here.

I have a hard time believing that anything from d-u has changed your swappiness value, if you set it in /etc/sysctl.conf. On a system I built and configured last November, it remains exactly as I originally set it:

procfs is a virtual filesystem, an interface to your running kernel, nothing you do there survives a reboot.

smoo

Post subject:Posted: 16.05.2011, 17:23

Joined: 2010-10-20
Posts: 10

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Yeah, I of course change the swappiness value in a "permanent" way through /etc/sysctl.conf, and thought it would persist across dist-upgrades. That's why I was (and am) confused as to why the swappiness is back at the old value of 60!

I'll keep an eye on this. Thanks for the suggestions.

lab

Post subject:Posted: 17.05.2011, 05:52

Joined: 2010-09-18
Posts: 17

Status: Offline

smoo wrote:

Yeah, I of course change the swappiness value in a "permanent" way through /etc/sysctl.conf, and thought it would persist across dist-upgrades. That's why I was (and am) confused as to why the swappiness is back at the old value of 60!

I'll keep an eye on this. Thanks for the suggestions.

Did something perhaps upgrade /etc/sysctl.conf and you answered yes a bit too quickly? Is there a /etc/sysctl.conf.old or some such lying around? I did latest D-U a couple of days ago, and my value of 10 is still persisted just fine.

smoo

Post subject:Posted: 18.05.2011, 13:35

Joined: 2010-10-20
Posts: 10

Status: Offline

Quote:

Did something perhaps upgrade /etc/sysctl.conf and you answered yes a bit too quickly? Is there a /etc/sysctl.conf.old or some such lying around?

The former is possible, I guess. I can never rule out my own mistakes!

The latter isn't, or at least there is no backup version of /etc/sysctl anywhere that I can find.

At this point, despite being told that very few things other than operator error are ever going to change the swappiness value, it's my only option, as I certainly didn't leave it dat 60, and these two computers have been dist-upgraded often (~ once a day at work, when there aren't showstopper problems and perhaps once a week at home), and the problem hit them both within a few days or a week.

Anyway, I've changed those values to much lower values, and the problem is apparently gone for me now.